Interactive Histograms with Geogebra
The new version of Geogebra has several nice new features which make it much more useful for a range of statistical uses. Firstly, it comes with a simple spreadsheet-style view, which allows you to enter and manipulate data in a grid of cells, similar to a spreadsheet. Secondly, it has a number of new statistical functions, covering a range of data creation, summation, and visualisation options.
Here is an applet which demonstrates a couple of these new features. It takes 50 random values, generated to fit a Normal(8,4) distribution, and plots a box-and-whisker plot and a histogram.
All this just uses what are now built-in features of Geogebra. My contribution is to make the histogram interactive: move the blue points on the x-axis around to alter the class boundaries. This lets you explore the ways that small changes to the class intervals can sometimes have large effects on the histogram.
Enable Java to see this Geogebra applet.(Source: adjustable_histogram.ggb.)
Double click on a cell in the spreadsheet view to change its value. Also, just as in Excel, press F9 while in the spreadsheet view to regenerate all the random numbers. You may see the purple x-axis points move: they have been constrained to always be below the minimum and above the maximum value.
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Tags: applet, histograms, statistics